Transplantation of fat carried out today is mostly done by fat suction from a body, centrifuging/cleaning the fat in order to achieve a concentrate of fat cells and injecting the concentrate into the body, preferably by means of an injection needle. The problem concerning this method of transplanting is that 60-100% of the injected fat will be absorbed by the body within a year.
It is known that segmental or core fat, i.e. fat not being centrifuged/cleaned but with intact morphology/structure, will not be absorbed in a corresponding way when it is transplanted into a body. Studies on animals have shown a degree of absorption below 5%. See Fagrell, D.; Enestrom, S.; Berggren, A., et al. Fat cylinder transplantation: An experimental comparative study of three different kinds of fat transplants. Plastic and Reconstructive Surgery 98: 90, 1996.
One problem with transplanting tissue is the difficulty in extracting tissue of suitably small dimensions. Another problem concerns implanting the tissue with sufficient precision.
U.S. Pat. No. 5,269,316 shows a surgical instrument for removal, transplantation or implantation of corium, fat, cartilage or alloplastic material. The instrument is composed of three severable adjacent sections, the first which is a hollow scalpel, the second a hollow tube in communication with the hollow scalpel and the third is a solid portion tapered to a sharp needle.
The hollow scalpel and the solid sharp needle are severable from an end each of the hollow tube and the hollow tube is separable along its length after removal of the hollow scalpel and the sharp needle portion.
When using the instrument the sharp needle portion is fastened in a surgical drill so that the hollow scalpel can be introduced into a body through the skin at a first position, in a drilling fashion, and through the tissue to be extracted and finally out through the skin at a second position, thus making two wounds in the skin. It is difficult to see how this could work in practise since there seems not to be any evacuation of air from the inside of the hollow tube so when the tissue to be extracted should move into the hollow tube it will soon be stopped by an air cushion present inside the hollow tube.
Thereafter, the instrument is removed from the drill, turned and fastened at the hollow scalpel instead. Now the drilling starts with the sharp needle portion at the position of the body were the implantation is to be carried out. The instrument is introduced through the skin at a first position, along the path for transplantation and out through the skin again at a second position, thus making another set of two wounds in the skin.
The drill is removed and the hollow scalpel and the sharp needle portion are severed from the hollow tube, which is positioned inside the body. The hollow tube is then split into two halves still inside the body and withdrawn from the body leaving the transplanted tissue inside the body. It seems to be rather difficult to perform this separation and it will also cause an enlargement of the implantation cavity during the separation of the two parts as they need to be pushed radially away from each other in order to severe the two parts.
A problem with this surgical instrument is that it makes two holes in the skin, both when extracting tissue and when implanting tissue. Another problem is that the needle portion is sharp causing the tissue around the implanted tissue to bleed, which endanger the result of the transplantation increasing the risk of necrosis and/or rejection of the implanted tissue by the body. It also increases the risk of nerve, blood vessels and surrounding tissue injuries. Overall it seems to be a very circumstantial method.
In a recent article a new method is described for extracting core fat and implanting it. The article was published in Plastic and Reconstructive Surgery July 2007. It is called Facial Augmentation with Core Fat Graft: A Preliminary Report by Bahman Guyuron and Ramsey K. Majzoub.
The authors of the article have taken a 1 ml syringe and obliquely cut off the tip with an oscillating saw. A small incision was made in the extraction site of the body and the surgeon rotated and advanced the syringe while gently pulling the syringe piston to accommodate the fat.
A pair of baby Metzenbaum scissors or the same syringe containing the extracted fat was used to create a space at the implantation site and the syringe was introduced into the space. While the syringe was removed the syringe piston was used to deliver the fat into the newly made space. The syringe was introduced up to four times in the newly made space to deliver about 1 ml core fat per time.
One problem with this method is that it can only be used for fat as the oblique syringe is blunt and that also means it will not work for smaller dimensions either. Another problem is that when creating a space in the tissue at the implantation site the tissue will be severed by the scissors and the scissors will cause a larger inlet opening than needed for the implant and it is difficult to create a longer or deeper space with scissors. Or if the oblique syringe will be pushed into the tissue it will also severe the tissue. The tissue will be traumatized and will bleed. There will also be a risk of injuries to nerves, blood vessels and surrounding tissue.
It will be difficult to fill the space several times, and difficult to find the space each time, especially if it is cut with the scissors. At every time the syringe is inserted into the space there will be a risk of further severing of the tissue. It will be difficult to control the implantation, for example to position the fat at the right position and the right amount.
Placing a strong negative pressure with the syringe piston, which is needed when using a blunt tip, to the extracted fat will traumatize the fat as well as the last step of the extraction when the fat will be torn off the body. It will be impossible to control the extraction of the tissue since it will not be possible to know at which position the fat will be torn off the body, if it will be outside the extraction tube, inside the extraction or at its inner end. Neither will it be possible to control the shape of the extracted tissue as is evident from the picture of the article where the fat has different cross sectional size along its length.
All bleeding at the implantation site or traumatization to the fat will increase the risk of rejection of the fat at the implantation site.
The fat transplantation technique described by Bahman Guyuron and Ramsey K. Majzoub and the clinical results indicate that the method is crude. The extraction technique is limited to certain dimensions of fat tissue that is traumatized and not sharply cut. The fat implantation is likely to produce bleeding at the implantation site and the position of the implanted material is not exactly controlled.